Scaling of electric field fluctuations associated with the aurora during northward IMF

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Abstract

[1] We present a statistical study of scaling features of the electric field fluctuations measured by the DE2 satellite in the polar region during positive Bz IMF when the theta-aurora was observed by the DE1 satellite. It is demonstrated that the power spectra of the fluctuations have a power-law form at spatial scales from ∼0.5 km (the limit of resolution) to several thousands of kilometers, with a break near 100 km. The scaling properties of the field are studied by examining the generalized structure functions (GSFs) and probability density functions (PDFs) of the fluctuations. The observed PDFs have a non-Gaussian shape with heavy tails. We also demonstrate a collapse of the re-scaled PDFs onto a single curve. A relation of PDF shape to solar wind conditions is revealed. The same analysis is performed on the TV observations of the theta-aurora. The scaling characteristics of the field and auroral fluctuations are compared.

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